新增 undo 功能

client/src/pages/eq/components/FreqChart.tsx

@@ -7,6 +7,7 @@ import {
 } from "@/lib/peqAudio";
 import type { PeqEqUi } from "../constants";
 import { eqInterp } from "../utils";
+import { PeqUndoButton } from "./PeqUndoButton";
 
 /* ── Legend indicator ── */
 function LegendCurveIndicator({
@@ -37,6 +38,8 @@ export function FreqChart({
   abMode,
   onAbToggle,
   onCopyAndSwitchTo,
+  canUndo,
+  onUndo,
   onApplyB,
   onSaveB,
   onBandDrag,
@@ -52,6 +55,8 @@ export function FreqChart({
   abMode: "A" | "B";
   onAbToggle: (m: "A" | "B") => void;
   onCopyAndSwitchTo: (to: "A" | "B") => void;
+  canUndo: boolean;
+  onUndo: () => void;
   onApplyB: () => void;
   onSaveB: () => void;
   onBandDrag: (idx: number, patch: Partial<{ freq: number; gain: number }>) => void;
@@ -295,6 +300,11 @@ export function FreqChart({
           }}>
           {copyButtonText}
         </button>
+        <PeqUndoButton
+          disabled={!canUndo}
+          label={eqUi.undo ?? "Undo"}
+          onClick={onUndo}
+        />
         </div>
         <div className="ml-auto flex shrink-0 items-center gap-2">
         <button

client/src/pages/eq/components/PeqUndoButton.tsx

@@ -1,4 +1,3 @@
-import { Undo2 } from "lucide-react";
 import { cn } from "@/lib/utils";
 
 type PeqUndoButtonProps = {
@@ -8,6 +7,11 @@ type PeqUndoButtonProps = {
   className?: string;
 };
 
+const pillStyle = {
+  background: "rgba(44,44,46,0.7)",
+  border: "1px solid rgba(255,255,255,0.08)",
+} as const;
+
 /**
  * EQ page undo control — disabled when the undo stack is empty.
  */
@@ -25,22 +29,15 @@ export function PeqUndoButton({
       title={label}
       onClick={onClick}
       className={cn(
-        "w-9 h-9 rounded-full flex items-center justify-center transition-colors active:scale-95",
+        "px-3 py-1 rounded-[8px] text-[11px] transition-colors",
         disabled
-          ? "text-white/25 cursor-not-allowed"
-          : "text-white/70 active:text-white",
+          ? "text-white/25 cursor-not-allowed opacity-50"
+          : "text-white/50 active:text-white",
         className,
       )}
-      style={{
-        background: disabled
-          ? "rgba(44,44,46,0.45)"
-          : "rgba(44,44,46,0.8)",
-        border: disabled
-          ? "1px solid rgba(255,255,255,0.06)"
-          : "1px solid rgba(255,255,255,0.1)",
-      }}
+      style={pillStyle}
     >
-      <Undo2 size={18} />
+      {label}
     </button>
   );
 }